Hyaluronic acid is naturally found in many tissues of the body such as skin, cartilage, and the vitreous humor. Hyaluronic acid can be used to treat osteoarthritis of various diarthrodial joints, e.g., knee joints, hip joints, etc. In order to properly treat certain diarthrodial joints, e.g., hip joints, it is desirable to inject hyaluronic acid deep into a joint capsule of the diarthrodial joint—regardless of patient size. As such, it is desirable to locate synovial fluid associated with a diarthrodial joint and it is desirable to locate a tip of an injection needle prior to injection of the hyaluronic acid within a joint capsule.
Accordingly, there is a need for a device for locating synovial fluid in a patient and for locating a needle tip within a patient prior to injecting a therapeutic agent such as hyaluronic acid.